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6. system of particles and rotational motion — Physics STD 11 Science — Question

Rajasthan BoardEnglish MediumSTD 11 SciencePhysics6. system of particles and rotational motion1 Mark
MCQ
Three point masses $m_1, m_2$ and $m_3$ are placed at the corners of a thin massless rectangular sheet ($1.2 \,m \times$ $1.0 \,m$ ) as shown. Centre of mass will be located at the point ........... $m$
  • A
    $(0.8,0.6)$
  • B
    $(0.6,0.8)$
  • ✓
    $(0.4,0.4)$
  • D
    $(0.5,0.6)$
✓

Answer

Correct option: C.
$(0.4,0.4)$
c
(c)

$x_{ cm }=\frac{m_1 x_1+m_2 x_2+m_3 x_3}{m_1+m_2+m_3}$

$y_{ cm }=\frac{m_1 y_1+m_2 y_2+m_3 y_3}{m_1+m_2+m_3}$

$x_{ cm }=\frac{(1.6)(0)+(2.4)(0)+2(1.2)}{1.6+2.4+2}=0.4 \,m$

$y_{ cm }=\frac{(1.6)(0)+(2.4) 1+2(0)}{1.6+2.4+2}=0.4 \,m$

$\text { So, }\left(x_{ cm }, y_{ cm }\right)=(0.4,0.4) \,m$

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